1. Technical Field
The present disclosure relates to a liquid ejection apparatus that ejects a liquid and a method for manufacturing the liquid ejection apparatus.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2006-123518 discloses, as a liquid ejection apparatus, an inkjet head that records an image and the like by discharging ink onto a recording medium. The inkjet head of Japanese Unexamined Patent Application Publication No. 2006-123518 includes a channel defining substrate in which a plurality of pressure chambers are formed and a piezoelectric actuator provided in a diaphragm of the channel defining substrate that covers the plurality of pressure chambers.
The piezoelectric actuator includes a plurality of piezoelectric elements that are disposed on the diaphragm so as to correspond to the plurality of pressure chambers. Each piezoelectric element includes a piezoelectric portion (a piezoelectric layer) formed of lead zirconate titanate, a lower electrode that is formed of platinum and iridium and that is disposed on a lower side of the piezoelectric portion, and an upper electrode that is formed of iridium and that is disposed on an upper side of the piezoelectric portion. A first lead electrode formed of aluminum is connected to an end portion of the upper electrode that is positioned on an upper surface of the piezoelectric portion. The first lead electrode is drawn out from the upper surface of the piezoelectric portion to above the diaphragm, and is extended along a surface of the diaphragm. Furthermore, the piezoelectric portion, the upper electrode, and the first lead electrode are commonly covered by a protective film formed of aluminum oxide. Furthermore, a second lead electrode formed of gold is formed on the protective film. Furthermore, the first lead electrode is connected to the second lead electrode on the protective film at a position away from the piezoelectric element through a contact hole formed in the protective film.
The piezoelectric actuator described above is manufactured by repeating deposition and patterning and by sequentially stacking each of the various films, such as the piezoelectric portion and various electrodes, on the diaphragm that covers the plurality of pressure chambers of the channel defining substrate. First, the lower electrode, the piezoelectric portion, and the upper electrode of each piezoelectric element are formed on the diaphragm in that order. Next, the first lead electrode that is connected to the upper electrode and that extends from the upper surface of the piezoelectric portion to the upper surface of the diaphragm is formed. Each first lead electrode is formed by depositing a metal film and then patterning the metal film. Next, the protective film is formed so as to cover the piezoelectric portion, the upper electrode, and the first lead electrode. Furthermore, patterning of the protective film is performed and a contact hole is formed in a portion of the protective film covering a terminal of the first lead electrode. Last of all, the second lead electrode is formed on the protective film and, at this point, the second lead electrode is brought in contact with the terminal of the first lead electrode through the contact hole.